The usefulness of home monitors in the management of apnea of infancy (AOI) and other risk groups for Sudden Infant Death Syndrome (SIDS) has yet to be established. This application is in response to an RFA to participate in a cooperative agreement to perform a multi-center collaborative study regarding the usefulness of home monitors in the management of AOI, preterm survivors, and subsequent siblings of SIDS victims. This application is being submitted for an award as a Clinical Unit and as the Clinical Trial Operations Center. The specific aims are to improve the efficacy of home monitoring, determine monitor compliance, and identify the physiological parameters of cardiorespiratory events occurring in normal infants and in infants at increased epidemiological risk for SIDS. These aims are now possible using new technologies for documented monitoring including O2 saturation (SaO 2) . The goals of this collaborative study are to (1) determine the frequency, duration and type of cardiorespiratory alterations in normal infants and in infants at risk for apparent life-threatening events (ALTEs), recorded with state-of-the-art technology, (2) determine compliance with home monitoring, and (3) characterize the physiological and clinical significance of documented alarms/events. During Phase I (12 months), the Steering Committee will finalize the specific study objectives, develop the standard protocol and data forms including standard scoring/analysis strategies for event recordings and pneumograms, adopt a manual and training programs for the event recording technology and parent education, and adopt common protocols for autopsy and death-scene investigations for all infant deaths. The actual study will be conducted over the next 44 months, leaving the final 6 months to complete all data analysis. A total of 300 at-risk subjects will be enrolled annually: 150 AOI, 100 preterm survivors less than 2000 grams birth weight and 50 subsequent siblings of prior SIDS or prior ALTE. State-of-the-art documented monitoring will be performed in each subject, using the HealthDyne Smart Monitor (970S) and the integrated pulse oximeter (930). 5-channel pneumograms will be performed at the time of enrollment as part of standard clinical care, and follow-up pneumograms will be obtained and correlated with clinical status and the event recordings. The primary outcome variable will be the occurrence of ALTEs, estimated to occur in 5-10% of subjects. As the Clinical Trial Operations Center, the applicant will provide administrative and scientific support for the Clinical Units and will supervise the acquisition and management of the clinical data in cooperation with the Data Coordinating and Analysis Center. This RFA is related to the priority area of infant health, and will lead to a better understanding of cardiorespiratory pattern maturation and SaO2 in infants at increased risk for ALTEs, the effectiveness of documented monitoring in maximizing compliance, and of the physiological characteristics of ALTEs in infants at increased risk for SIDS.